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DCM - What is it?

Dilatative cardiomyopathy (DCM) is a myocardial disease that manifests itself in a pumping weakness of the heart muscle. Due to the resulting under-supply of the body circulation with blood a low
blood pressure results. The body tries to increase the blood volume by means of fluid resorption in the kidneys and dilating the blood vessels with different neurohormonal compensatory
mechanisms. First this sounds good and also causes the blood pressure to rise. However, the heart cannot cope with the increased load caused by the higher blood volume. In addition, the heart
must now pump the blood against a higher resistance due to the constricted blood vessels. As a result, the heart muscle increases its muscle mass, resulting in dilatation - the heart's muscles
grow apart, the main chambers are enlarged and the heart is additionally damaged. In the further development, the body is no longer optimally perfused in the front, while "backward" causes
congestion and thus oedema (eg pulmonary oedema) or occasional effusions (eg ascites or pericardial effusions).Often cardiac arrhythmias occur during the course of this disease, which in some
cases may also result in sudden cardiac death.

Depending on the time of their occurrence, one speaks of DCM in a juvenile form (<1 year) or in adult form (2-6 years).

In addition, the DCM runs in two phases that follow one another. The course of the disease begins with the subclinical (also occult or hidden) phase, which runs unnoticed and without
symptoms. Only in the subsequent clinical phase symptoms show such as cough, weakness of performance and fainting.

The possibility that a dog is completely unnoticed in DCM, because he is still in the subclinical phase, once again shows the importance of preventive
cardiac ultrasound.

(hand drawn, based loosely on http://www.transplantation-verstehen.de/dotAsset/25070.jpg)

Which forms of DCM do exist?

DCM is one of the acquired hereditary diseases (explanation here) and can have several causes:

The primary DCM can be idiopathic (= with unknown trigger) or genetic. Once a disease occurs more often within a particular breed or within a
family, a genetic cause can be assumed. In a 1999 study with dogs in the US, the Labrador Retriever was in position 12 of the DCM affected breeds. At this time the figures for Germany could not
be confirmed, but according to Dr. Kresken, this has changed in recent years. Of the Labrador Retrievers involved in DCM, approximately 80% are male animals.

The secondary DCM is due to various system diseases but can also be caused by certain drugs (e.g. chemotherapeutics). Possible causes are the
following:

nutritive (food-related) cause: carnitine and / or taurine deficiency – the exact correlations are unfortunately unclear, whereby a
hereditary defect in the carnitine / taurine metabolism seems to be relevant for the development of the DCM

toxic influences – certain chemotherapeutics can damage the heart muscle as cell poisons and cause a DCM; In dogs, however, this has not
yet been described

inflammatory causes – DCM can also be caused by viruses and bacteria that cause myocarditis

endocrine (hormonal) influences – the hypothyroidism can have a negative influence on the contractility of the heart muscle and thus have
an influence on the development of a DCM, but the changes in the heart are hardly visible in this context